<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    body{
      margin: 0;
      padding: 0;
    }
    .left{
      float: left;
      width: 200px;
      height: 100%;
      background: salmon;
    }
    .main{
      height: 100%;
      background: rosybrown;
      overflow: hidden;
    }
    .margin{
      width: 200px;
      height: 200px;
      background: salmon;
      margin: 10px;
    }
    .outer{
      width: 100%;
      overflow: hidden; /* 清除浮动 */
      border: 10px solid sandybrown;
    }
    .inner{
      width: 200px;
      height: 200px;
      float: left;
      margin-right: 5px;
      background: rosybrown;
    }
  </style>
</head>
<body>
  <!-- 左固定右自适应布局<div class="left">
    left
  </div>
  <div class="main">
    maincccccc
  </div> -->
  <!-- BFC margin 重叠 
  <div class="margin">
    one
  </div>
  <div class="margin">
    2222
  </div> -->
  <div class="outer">
    <div class="inner">left</div>
    <div class="inner">right</div>
  </div>
</body>
</html>